1. Field of the Application
The invention relates generally to breastpumps for drawing breastmilk, and particularly to a new way to operate a breastpump, such as a motorized, electrically driven breastpump, to better simulate an infant during breastfeeding.
2. Description of the Related Art
Breastpumps for use by nursing mothers are well known. They allow the nursing woman to express the breastmilk as necessary or convenient, and further provide collection of the breastmilk for later use. For some mothers, breastpumps may be a necessity, such as when the mother is away from the child (as at work), the child has suckling problems, or if the mother has problems with excessive or deficient milk production, or soreness, deformation or injury of the mammilla.
Historically, electrically driven motorized breastpumps have been made with a single type of “cycle” for a given pump. That is, the driving mechanism for generating the vacuum (negative pressure) to be applied at the breast is geared to a particular sequence, or curve, of negative pressure increase (i.e., increasing suction), and then release. This is often aimed at reproducing in some sense the suckling action of an infant, for instance. Breastpumping can cover a range of different conditions, however, such as where the mother's nipples are sore for some reason, there is a state of significant engorgement, some nipple stimulation may be particularly desired, let-down and relaxation may be of particular interest, it may be desired to increase milk production, and so on.
Some breastpumps have provided the user with the ability to vary the amount of peak vacuum being applied, as well as the speed of the pumping action (i.e., number of cycles per minute, or frequency). The basic “curve” or sequence remains fixed, however, and the user must adapt as best she can to making variations within that particular curve built into the machine, which typically has been generalized for the overall population of users. FIG. 1 shows such a prior art sequence that yields a simple smooth curve between a maximum vacuum and ambient conditions (negative pressure is along the y-axis (in millimeters of mercury) and time (in seconds) along the x-axis). Note how the cycle depicted repeats itself (here, every 1.25 seconds).
The SYMPHONY breastpump by Medela, Inc., which is the subject matter of U.S. Pat. No. 6,547,756, introduced both a breastpump that can be programmed to generate a plurality of differing milk expression sequences or curves, as well as the ability to now generate a sequence that had special inflections, or modifications, that differed from a smooth curve. In FIG. 2, which is the Superior program, note how the maximum negative pressure peak (P1) is followed by a slight pause (P2), thereby yielding a curve shape that is different from that of the standard curve of FIG. 1. Although providing a number of choices for the mother in the way of different shaped curves, each of these programs is predictable and regular, i.e., the cycle or sequence repeats itself (at least while that particular sequence is in operation, since a plurality of different sequences may be used in a session, e.g., letdown, then an expression sequence.
This type of regularity, however, is not presented by an infant when breastfeeding. During breastfeeding, an infant does not suck in a regular repeatable pattern, but rather pauses at times, and may further change the level of force applied (e.g., suction) and even the rate in rapid fashion. It is therefore the consideration of this invention to better simulate an infant during breastfeeding by providing a breastpump that can be operated to generate milk expression sequences or curves with some irregularity or randomness therein.